Randomize

Syntax:

    Randomize
    Randomize seed

Command Availability:

Available on all microcontrollers

Explanation:

Randomize is used to seed the pseudo random number generator, so that it will produce a different sequence of numbers each time it is used.

The random number generator in GCBASIC is a 16 bit linear feedback shift register, which is explained here: http://en.wikipedia.org/wiki/Linear_feedback_shift_register

Generally, you will get the same sequence every time it is used.  However, you can seed it so that it will start at a different point at the sequence using the Randomize command.

If you wanted to use an analog reading to seed the generator, this would work:

Randomize ReadAD10(AN0)

If no seed is specified, then the RANDOMIZE_SEED constant will be used as the seed.  If seed is specified, then it will be used to seed the generator.

It is important that the seed is different every time that Randomize is used. If the seed is always the same, then the sequence of numbers will always be the same.   It is best to use a running timer, an input port, or the analog to digital converter as the source of the seed, since these will normally provide a different value each time the program runs.

Example:

    'Set chip model
    #chip tiny2313, 1

    'Use randomize, with the value on PORTD as the seed
    Randomize PORTD

    'Generate random numbers, and output on PORTB
    Do
        PORTB = Random
        Wait 1 s
    Loop
Prev  Up  Next
  Home